Interpretive Summary: In this research, we have been working with a class of enzymes from bacteria that have multiple functions. Although their “natural” function seems to be to convert sugar into polysaccharides (gums and fibers), they can also produce small sugar molecules that have use as low-calorie or low-glycemic sweeteners, as well as prebiotics for intestinal health. This paper describes the chemical structure of one such small sugar molecule, and corrects a piece of misinformation that has persisted in the literature for over 40 years. It also shows that some of our patented enzymes are much more efficient at making these small sugar molecules, which may be of interest to food ingredient manufacturers.

Technical Abstract:
The main acceptor product of glucansucrases with D-mannose has not previously been identified. We used glucansucrases that form water-insoluble a-D-glucans to produce increased yields of acceptor products from D-mannose, and identified the major product as 6-O-a-D-glucopyranosyl-D-mannose. Glucansucrases that synthesize insoluble a-D-glucans produced higher yields of the disaccharide compared to typical dextransucrases.